The present invention relates to a semiconductor device and a method of manufacturing the semiconductor device.
A semiconductor device has been miniaturized in recent years. As miniaturization has proceeded, the width of metal wiring lines in the device has narrowed, and, therefore, an aluminum comprising copper of about 0.5% by weight is generally used to prevent disconnection of a wire, or a hillock, in an aluminum wiring line due to migration.
However, in the case of the aluminum wiring line containing copper, there is a case where copper atoms are precipitated. The location of precipitation is around a grain boundary or an interface between an adjacent conductor layer and a main wiring layer. Especially, when a precipitate become large around the interface, there is a case where the precipitates remain there since the precipitate is not etched. In the case where a wiring interval (space between wirings) is narrow, it is a cause of short circuit failure between adjacent wiring lines.
Since there is a tendency that not only a width of the wiring line but also an interval between wiring lines narrow, the problem of short circuit failure can be serious. Then, for example, Japanese Patent Laid Open No. 186175/1996 discloses a method in which after forming an aluminum film and dissolving copper into the aluminum at high temperature, rapid pooling is carried out to prevent copper precipitates at the cooling.
To prevent short circuit failure between wiring lines, the method of manufacturing an aluminum wiring line containing copper by rapid cooling treatment is not satisfactory in the case where the semiconductor device has less than a 0.4 xcexcm interval between wiring lines. In order to prevent short circuit failure between wiring lines, especially, it should be prevented that copper precipitates around the interface between an adjacent conductive layer and an aluminum wiring layer.
Therefore, an object of the present invention is to provide a semiconductor device having a wiring structure in which a short circuit can be avoided.
Furthermore, another object of the present invention is to provide a semiconductor device having high reliability.
Another object of the present invention is to provide a semiconductor device having high productivity.
A semiconductor device of the present invention comprises a semiconductor substrate, a wiring line overlying a main surface of said semiconductor substrate, and an insulating layer adjacent the wiring line. The wiring line has a main wiring layer, and the main wiring layer has a main constituent element and an added material (e.g., element). The concentration of the added material at a first portion in the main wiring layer is higher than that at a second portion, the second portion being closer to the insulating layer than said first portion of the main wiring layer is to the insulating layer. Desirably, the wiring line includes the main wiring layer and an adjacent conductor layer located between the main wiring layer and the insulating layer, and the second portion of the main wiring layer, having the lower concentration of the added material than the first portion, is closer to the interface of the main wiring layer and adjacent conductor layer than the first portion is to this interface.
Besides, a semiconductor device of the present invention includes a semiconductor substrate, a wiring line overlying a main surface of the semiconductor substrate, and an insulating layer adjacent the wiring line. The wiring line has a main wiring layer and, e.g., an adjacent conductor layer located between the main wiring layer and the insulating layer. The main wiring layer can be made of aluminum as a constituent (main) material and copper as an added material, and the adjacent conductor layer can be made of titanium or titanium nitride as a constituent material. Illustratively, as an alternative the constituent (main) element of the main wiring layer can be copper, with nickel as the added material; moreover, the adjacent conductor layer can be made of ruthenium. The concentration of the added material in a first portion in the main wiring layer is higher than that in a second portion located closer to the interface with the adjacent conductor layer than the first portion of said main wiring layer is to this interface.
Besides, a semiconductor device of the present invention comprises a semiconductor substrate, a wiring line on a main surface of said semiconductor substrate, and an insulating layer adjacent said wiring line. The wiring line has a layered structure. The layered structure has a layered main wiring layer and, e.g., an adjacent conductor layer located between said main wiring layer and said insulating layer. Said layered main wiring layer has a first main wiring layer, and a second main wiring layer located between said first main wiring layer and said adjacent conductor layer. A concentration of added material in said first main wiring layer is higher than that in said second main wiring layer.
Furthermore, the semiconductor device of the present invention can have the following: the concentration of copper in said first main wiring layer or first portion can be 0.4% by weight or more, and the concentration of said copper in said second wiring layer can be from 0% to 0.2% by weight (including the end points). Illustratively, and not to be limiting, the high-concentration portion of the wiring layer can have up to 5% by weight copper.
Besides, a semiconductor device of the present invention includes a semiconductor substrate, a wiring line overlying a main surface of the semiconductor substrate, and an insulating layer formed adjacent the wiring line. The wiring line has a layered structure. The layered structure has a layered main wiring layer and an adjacent conductor layer located between said main wiring layer and said insulating layer. Said main wiring layer has a first main wiring layer and a second main wiring layer located between said first main wiring layer and said adjacent conductor layer. The thickness of said second main wiring layer is from 5 nm to 40 nm. Illustratively, and not to be limiting, the first main wiring layer can have a thickness of 50 nm or more, and 3000 nm or less.
Furthermore, the semiconductor device of the present invention can have the following: the thickness of said second main wiring layer is from 5 nm to 40 nm, or, a part of said wiring line is formed a smaller distance than 0.4 xcexcm (e.g., illustratively, and not to be limiting, about 50 nm, based upon present manufacturing machine capabilities) from another part of the wiring line located separately from the first-mentioned part of the wiring line.
Furthermore, the semiconductor device of the present invention can have the following: the first main wiring layer and the second main wiring layer have a same material as a constituent (main) element.
Besides, a semiconductor device of the present invention comprises a semiconductor substrate, a conducting means for conducting electricity overlying a main surface of said semiconductor substrate, and a layer for insulating said conducting means adjacent said conducting means. Said conducting means has main conducting means for conducting electricity and, e.g., an adjacent conducting means for obstructing movement of constituent material and/or added material of said main conducting means to said insulating means and located between said main conducting means and said insulating means. Said main conducting means has first main wiring means for conducting electricity and second main wiring means for obstructing movement of said added material of said first main wiring means toward said adjacent conducting means through said second main wiring means.
In the semiconductor device of the present invention, for example, said conducting means may be the wiring line, said insulating means may be the insulating layer, said main conducting means may be the main wiring layer, said adjacent conducting means may be the adjacent conducting wiring layer, said first main wiring means may be the first main wiring layer, and said second main wiring means may be the second main wiring layer. The semiconductor device of the present invention further includes that said first main wiring layer and said second wiring layer can have a same material as the constituent element.
Besides, a method of manufacturing a semiconductor device of the present invention comprises forming a first insulating layer on a semiconductor substrate, and forming a wiring line overlying said first insulating layer. A second insulating layer can be formed on said wiring line. The process of forming the wiring line comprises forming a first main wiring layer overlying the first insulating layer, and forming a second main wiring layer on said first main wiring layer, whereby the concentration of an added material in said first main wiring layer is less than that in said second main wiring layer. Desirably, the process of forming the wiring line includes forming an adjacent conductor layer on the first insulating layer, forming the first main wiring layer on the adjacent conductor layer, and forming the second main wiring layer on the first main wiring layer. The first and second main wiring layers have relative amounts of the added material as discussed previously. Alternatively the wiring line can be formed by forming the adjacent conductor layer and forming a main wiring layer on the adjacent conductor layer; the main wiring layer can have a varying concentration of an added material therein, from a relatively low concentration at the adjacent conductor layer to a higher concentration spaced from the adjacent conductor layer.
The method of manufacturing a semiconductor further can comprise wherein said main wiring layer comprises aluminum as a constituent (main) material and copper as the added material, and said adjacent conductive layer comprises titanium or titanium nitride as a constituent material. In the method of manufacturing a semiconductor device as in the present invention, the concentration of copper in the first main wiring layer can be 0.4% by weight or more, and that in second main wiring layer can be from 0% to 0.2% by weight. In the method according to the present invention, said second main wiring layer can be formed at 550xc2x0 K or more, and said second main wiring layer can be cooled rapidly (e.g., at least 100xc2x0 C./min). In the method according to the present invention, said second main wiring layer can be cooled rapidly by providing a fluid to cool.
Since the concentration of the added element in the vicinity of the interface between, e.g., the adjacent conductor layer and the main wiring layer is low, the generation of a precipitate in the vicinity of the interface can be suppressed, so that a wiring structure avoiding a short circuit can be obtained, and the object of the present invention can be achieved.
Further, since the semiconductor device having the wiring structure in which the short circuit is hard to cause is obtained, the semiconductor device having high reliability can be provided, and the semiconductor device having high yield can be provided, so that the objects of the present invention can be achieved.